Conventionally, power conversion apparatuses including a matrix converter have been in practical use (see Patent Literature (PTL) 1 and PTL 2, for example).
FIG. 20 is a circuit diagram of a matrix converter 200 disclosed in PTL 1. To drive a three-phase motor 203 using a single-phase AC power supply 201, the matrix converter 200 directly converts an input AC voltage supplied from the single-phase AC power supply 201 into a three-phase output AC voltage using bidirectional switches 202a to 202f, and supplies the output AC voltage of each phase to a winding of a corresponding phase of the three-phase motor 203.
Each of the bidirectional switches 202a to 202f includes two switching elements connected in inverse parallel, each capable of changing between a unidirectional conducting state and a non-conducting state. A magnitude determining unit 204 determines the magnitude relationship between the voltages at the terminals of the single-phase AC power supply 201. According to the magnitude relationship determined by the magnitude determining unit 204, a control unit 205 supplies a current to the windings of the three-phase motor 203 from the single-phase AC power supply 201, and controls the conduction of each of the bidirectional switches 202a to 202f to allow circulation of a regenerative current from the windings of the three-phase motor 203.
According to PTL 1, the matrix converter 200 having the above configuration allows the motor driving current to be stable, highly efficient, and highly reliable without a short circuit.
PTL 2 discloses a similar technique for driving a three-phase motor with a single-phase AC power supply, using a matrix converter.